public class ShuntYard
{
    interface INode
    {

    }

    interface ITerm extends INode
    {
        public Number getValue();
    }

    class IntegerNode implements ITerm
    {
        int value;


        public Number getValue()
        {
            return value;
        }
    }


    public static String getPostFix( String infix )
    {
        StringBuilder result = new StringBuilder();
        return result.toString();
    }

}
